1. Field of the Invention
The present invention relates to a method for making a fin for a heat sink, and particularly to a method for making a folded fin for a heat sink having a pair of vertical sections bent double. A machine is also disclosed for use with the method described.
2. Description of Prior Art
As heat generating components in a computer, such as CPUs and chips, contain more circuitry and operate at faster speeds, greater amounts of heat are generated, which must be dissipated for reliable operation. A heat sink made from a heat conductive material, such as aluminum, is commonly used to dissipate the heat generated by a heat generating component. The heat sink is retained in direct contact with the heat generating component to dissipate the heat into the surrounding environment.
A conventional heat sink 10 is shown in FIG. 12. The heat sink 10 comprises a plurality of fins 12 integrally formed by extruding. The manufacturing cost using this method is relatively high.
FIG. 13 shows another conventional heat sink 11 consisting of a base plate 13 and a heat dissipating member 14 attached together. The heat dissipating member 14 is formed by stamping a metal plate or by extruding from aluminum materials and comprises a plurality of U-shaped fins 142 interconnected by planar portions 144. The heat dissipating member 14 is attached to the base plate 13 by heat conductive epoxy adhesive or by rivets.
A problem with such an arrangement is that an additional fan must be used to enhance the heat dissipating effectiveness of the heat sink 11. The heat generated by a heat generating component 1 in phantom is transmitted to the base plate 13 and radiates from the base plate 13 via three paths as indicated by arrows A, B and C. The heat transmitted via the paths A and C easily dissipates into the surrounding environment. However, the heat transmitted via the path B tends to accumulate in a space 143 defined in the U-shaped fin 142 and does not dissipate as readily thereby degrading the heat dissipating effectiveness of the heat sink 11. Therefore, an additional fan (not shown) must be used to forcibly expel the heat from the space 143 in cooperation with the heat sink 11. However, the fan occupies space, consumes electric power and increases the cost. The noise made by the fan is a further disadvantage. Furthermore, the fan has a fixed life span and vibrates during operation thereby adversely affecting connections with other components.
Therefore, a heat sink, which has an enhanced heat dissipating capability without requiring use of a fan, is desirable. The present invention meets such a requirement by providing a heat sink having a plurality of folded fins.